1. Field of the Invention
The present invention relates to a heat-resistant hose for a vehicle, which is used in fields such as automobilse and construction machines, and more specifically, to a heat-resistant hose for a vehicle such as a turbo air hose to be mounted on a turbocharger system.
2. Description of the Related Art
Widespread use of turbocharger systems on vehicles has been advanced to improve thermal efficiency of internal combustion engines and respond to emission control as part of an environmental response. Air introduced from the turbocharger into an intercooler or the engine has high temperature and high pressure, and hence a hose material for transporting the air is required to have high heat resistance.
In view of the foregoing, a hose using a fluororubber composition in its inner layer and an acrylic rubber composition in its outer layer has been proposed (see JP-A-2004-17485 and JP-A-2010-42669).
However, the hose described in each of JP-A-2004-17485 and JP-A-2010-42669 has the following problem. Since the inner layer and the outer layer are subjected to vulcanization adhesion to each other with a peroxide crosslinking agent blended into each of the fluororubber composition and the acrylic rubber composition, their interlayer adhesive force is insufficient and interfacial peeling occurs. It should be noted that an approach involving adhering the inner layer and the outer layer to each other with an adhesive has been proposed, but it involves the following problem, namely, steps of applying the adhesive, drying the adhesive, and the like are needed, and hence the unit price of the product increases.